This week we are thrilled to have the Hammerhead Karoo2 Bike Computer Review. A genuine Garmin bike computer alternative for anyone looking at an upgrade.

Introduction to the Hammerhead Karoo2

The Hammerhead Karoo2 is the latest incarnation of the Karoo line up of cycling GPS computers from the now SRAM owned brand and is 40% smaller and 33% lighter than its predecessor with a promise of improved performance with a quad-core processor, Ant+, Bluetooth, Wi-Fi and cellular data connectivity, a 80mm / 3.2” anti-glare Dragontrail glass outdoor proof touch screen with an impressive 292PPI pixel density, which is just over half of what my Samsung Galaxy S10 has and I’m more than happy mirroring that to a big screen to watch the likes of GCN+ live racing of a bit of Netflix, so I was expecting big things from this head unit.

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What’s In The Box?

The Karoo2 comes in a very classy looking matte black box with a glossy Hammerhead logo on the front, again not unlike a quality mobile phone, but for the asking price of a penny under £360 it’s what you’d expect. You slide a further box out of the cover to reveal the Karoo2 head unit in the top half, underneath which is a little folder with guide on how to attach the unit to its proprietary mount and a – limited – user guide. At the bottom end of the box there is a pull-out drawer which contains said mount, a very handy Garmin quarter turn adapter, a 2.5mm hex key, USB-C charging cable and a lanyard for securing it to your bars once mounted.

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Hammerhead Karoo2 Dimensions

The head unit itself is pretty big, measuring just over 100mm tall and 60mm wide when compared to the likes of my current computer, the Wahoo Elemnt Bolt and the screen is 50% bigger, the unit is also heavier, but not in a bad way, more of a reassuringly weighty, this is a quality product way. It has a satin black finish with Hammerhead in Sliver on the underside at the front of the unit, two rubberised textured buttons on either side of the main scree and the matte finish touch screen, which I prefer to the glossy grey of the Wahoo.

If you turn the unit over you see the somewhat funky shaped proprietary mount and a coin slot cover for a mobile SIM, more of that later. On the bottom of the unit there are a pair of holes to attach the lanyard and the USB-C charging port with a tiny little bung in it that is rather fiddly to get out and not being captive, its more than likely that this will end up getting lost at some point, I haven’t managed to do so as of yet, but you never know, so this is one little thing that could definitely be improved upon. Slight update, after 100km of off MTB marathons at the weekend the bung is now somewhere on a Welsh mountain top, never to be seen again!

Charging the Hammerhead Karoo2 Bike Computer

Out of the box the Karoo2 had 52% change, so before firing it up for the first time I plugged in the supplied USB-C cable, attached it to a generic 2.0A mains charging plug and waited the two and a half hours it took to reach 100% charge; so, it’s safe to say that from flat the unit would take around 5 hours to charge, not bad, but not exactly fast and longer than my current Wahoo unit.

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The first time I started the Karoo2 a welcome screen came up and then a prompt to connect to a WiFi network, it then proceeded to download the latest software update which took a couple of minutes over my network at 5Mbps and was a simpler process than on my Wahoo which involves pairing with the associated app first. After the update had installed the initial set up started and I was prompted to download local (GB) offline maps with the option of installing others from all over the world.  You then go through various set-up and pairing screens where you are prompted to download the app for your phone, pair your Bluetooth and / or Ant+ sensors and if you have if your Shimano Di2 so you can control the head unit from the top buttons on your shifters, a nice feature. 

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Setting up the Hammerhead Karoo2 Computer

As for setting up data fields and number of data screens you have to head to the Hammerhead support page for a “how to”, once there it guides you through how to set up custom profiles and add whatever you want to display on several different screens, which you can scroll through by swiping left or right on the head unit, using the large buttons on either side or by using the buttons on the top of the Di2 shifter hoods. It’s all neat and very readable, even in bright sunshine with the screen brightness turned down.

Bike Mounting

For mounting the head unit to my bike, I opted to use the supplied Garmin adapter as my bikes all have that style of mount, it’s a nice touch and a plus point over the Wahoo that this is included, it clips in place securely and fits the various mounts I have perfectly. On the bike the unit looks quite stealthy in its matte finish and sits nicely. I did also attach the supplied lanyard, looping it round the bars, not something I usually do, but the last thing you want is a unit of this price bouncing off your bars on a rough off-road descent or even a sketchy patch of countryside tarmac.

User Experience

The ride / user experience out in the wild is for the most part excellent, data fields are easy to read, toggling between data pages are just a swipe or press of a button away and the display is easy to read. Battery life is claimed at 12 hours on the Karoo2, with a  tested burn rate of roughly 10%  an hour, thus equating to a maximum battery life of 10 hours, below claimed. But that is with a HRM, cadence sensor and Di2 paired along with the screen being set at 40% brightness, there is a battery save mode that reduces the burn rate slightly, but I very much doubt you’d get 12 hours out of the head unit.

Battery Life of the Hammerhead Karoo2

When using the navigating option, the burn rate increases to roughly 12% per hour, but unless you’re on a major multi-day adventure or are planning on riding for more than 10 hours you’ll be fine. You can run a piggyback power pack and charge while running, which is common on many GPS units.  One thing that does seem to affect battery life negatively is temperature, after a very cold – hovering around 0 degC – marathon in the Welsh hills, the unit had used 35% of its battery life in 2.5 hours, that’s with only a HRM connected.

Another glitch that is in there and if you look on the socials, is that the unit seems to have an issue with high power LED lights, I run an Exposure Maxx-D on the bars and when you change power levels it can cause the screen on the Karoo2 to swipe by itself to the next one, rather bizarre, but not a huge issue. In comparison the Wahoo Elemnt Bolt does 12 hours easily, but it’s not supporting a big colour screen or fancy mapping and routing ability so it’s all relative and for me, and more than acceptable.

Navigation Capabilities

Speaking of navigation and mapping, it’s excellent and a real strong point of the Karoo2 when compared to the Elemnt Bolt. The screen is clear in all conditions, the maps easy to read. You get a visual notification of the next turn or waypoint well before you need to make the change in direction, and it’s also accompanied by a beep to let you know something is coming up. So, if you’re into following routes on or off road this I would say is the perfect unit for you.

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An update to the firmware came out during the test period that allows you to set the Climber function to always be on, this is a great little feature that overlays the upcoming climb in graphical form when you’re out and about, previously this was only available in the navigation setting, so if you like to see what you’re about to grind up it’s all there in glorious technicolour. You can clear it off the screen by swiping down and get it showing again by swiping up from the bottom of the screen. 

Strava Integration

I’m a Strava user, well if it’s not on there did the ride even happen? And found the live segments pop up, which is overlaid on whatever data screen you’re on easy to read and see where you are compared to your PR and the King or Queen of the Mountain time, similar levels of data are displayed on the Wahoo Elemnt, but they’re far clearer on the Karoo2 and displayed in orange too, which is nice.

The post ride experience is as you’d expect from a modern cycling GPS, summary or speed, HR etc. shown and a map to show you where you’ve been, but there’s one overriding issue with the unit. While it does pair to the Karoo companion app, this is just for ensuring notifications come up on the head unit from our phone. The ride data does not automatically upload to Strava, Ride with GPS or whatever medium you’re using by being paired to your phone. You need to have an internet connection via WiFi or hotspot on your phone, which is a bit annoying and something that both Garmin and Wahoo have got nailed.

This is where the SIM card slot comes into play, where you can insert a SIM with a data plan and upload via that, but that comes at an additional cost and even on PAYG it’s an additional £5 per month that shouldn’t have to be paid and this is also how the live tracking works, not something I use, but I’m sure there are plenty of people out there do.

Mountain Bike Rides Review

I’ve done long road rides, 6-hour MTB races, XCO races winding in and out of trees in a forest, MTB marathons on open and very exposed Welsh hills in the wet, dry, warm and sub zero and other than the increased battery burn rate in the freezing temperatures the Karoo2 really is excellent, the GPS accuracy is in my experience bang on, elevation gain is where you’d expect it to be, gradients displayed are correct and even on lapped events the traces are more-or-less perfectly overlaid for the entirety of the race as you can see from the extract below.

Summary of the Hammerhead Karoo2 Bike Computer

Ultimately it comes down to one simple question, “Would I part with my hard-earned cash for a Karoo2?”  The unit itself is very well built, the screen is fantastic and easy to read, the functionality of the unit is great, set-up is simple, and it looks great. There are a couple of non-deal breakers that need sorting out, the silly little non-captive charge socket cover and the intermittent self-swiping when a high-power LED light is next to the unit, but they’re very minor niggles. The one thing that does need aligning with the likes of Wahoo and Garmin is the ride upload via Bluetooth, get this sorted and the Hammerhead Karoo2 is as close to the perfect cycling GPS as I’ve used. 

That being said, I would buy one as connectivity is easy and other than that the unit is excellent.

Best Price for the Hammerhead Karoo2

Buy the Hammerhead Karoo2 from Wiggle currently discounted to only £323.10

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